1. Field of the Invention
The present invention relates to packaging and particularly to packaging for products which are extemporaneously mixed. The invention is particularly suited to products such as those used in the field of hair colouring, where it is necessary to package a colorant solution intended for dyeing the hair and an oxidizing agent where the solution and the agent are not mixed until the product is to be used.
2. Description of the Related Art
A typical package used for products that are to be mixed before use includes a first bottle with a detachable stopper provided in its base, a second bottle, and connecting means for connecting the two bottles to each other so that their respective contents can be mixed within the two bottles. For example, patent FR 2,680,357 discloses packaging of this type in which the connecting means consist of a band shaped connecting piece which fulfils a number of functions. The connecting piece supports the stopper, provides a leaktight attachment between the first bottle and the second bottle and defines the outer trim for the region of connection between the two bottles. The connecting piece is snap-fastened onto the base of the first bottle, sealing being provided by force-fitting a portion of the connecting piece onto the first bottle. The sealing achieved by this type of fitting may sometimes prove insufficient, especially when the skirt formed by the base of the first bottle is of relatively large diameter, i.e. approximately 3 to 5 cm. The problem is that the quality to which such a bottle can be produced, and the tolerances on the dimensions exceed those of a conventional bottle, especially those made of thermoplastic. The precariousness of this type of seal is made all the worse by the fact that in the vertical position, the sealing region is immersed in the liquid, and this may unfavourably alter the properties of the thermoplastic, thus having an appreciable effect on the seal.
Furthermore, for such a connecting part to be threaded is precluded if the packaging, especially in the vicinity of the connecting piece, is of non-circular cross-section, such as an oval cross-section. This is because, owing to manufacturing tolerances, it would be impossible to guarantee an angular position which is precise enough to achieve alignment between the skirt-like trim and the exterior surface of the first bottle and thereby achieve leaktight clamping of the connecting part onto the first bottle.